辽宁省地震重点监视防御区Ⅱ类场地放大效应研究

AMPLIFICATION EFFECTS STUDY OF CLASS Ⅱ SITE IN THE KEY EARTHQUAKE MONITOR AND DEFENSE ZONE OF LIAONING PROVINCE

利用辽宁省地震重点监视防御区工程场地地震安全性评价工作中积累的大量实际钻孔和土工试验资料,在50年超越概率为63%、10%、2%三种地震动输入情形下,采用等效线性化方法研究了辽宁省地震重点监视防御区Ⅱ类场地土层的放大效应。研究结果表明辽宁省地震重点监视防御区50年超越概率10%的平均场地效应放大因子为1.37,若使用《中国地震动参数区划图(GB18306-2001)》认定的系数(1.25)将低估研究区域内的场地放大效应。50年超越概率2%情形即"工程结构抗倒塌水准"的平均场地放大效应因子为1.35。这些结果有益于为研究区域提供更为合理的抗震设防标准。研究同时发现,实际工程中使用单一变量或有限的几个变量去控制场地放大效应会有很大的离散,因此重大工程项目的地震安全性评价工作是不可被替代的。

a large number of practical drilling and geotechnical test data was accumulated through working in Liaoning seismic monitoring of key defense zone for seismic safety evaluation of engineering site. In the three seismic input cases which the exceedance probability in 50 years was separately 63%, 10% and 2%, the amplification effect of class Ⅱsite on the key monitor and defense area in Liaoning province has been studied. The results showed that the average site effect amplification of the key monitor and defense area in Liaoning province in 50 years beyond the 10% probability factor is 1.37. If use Seismic Ground Motion Parameter Block Plan of China （GB18306-2001）, the facor（1.25） in the study area will underestimate the site amplification effect. The average site amplification factor is 1.35 in the case of 2% exceedance probability in 50 years which is at the collapse resistance of structures level. These results are helpful for offering more reasonable seismic fortification criterion. The study also found that, to control the site amplification effects will be very discrete by using a single variable or a limited number of variables in the actual engineering. So the seismic safety evaluation of important engineering project work is irreplaceable.